Motor-controller.



C. E. HYATT. MOTOR CONTROLLER. APPLwATloN FILED Nov.12,191o.

Patnted July "i, 1914.

lwvmmlf -ffrrffff u a a ug, M

CIAliES E. HYATT, OF i-AST Gf 'NGE JERSEY, ASSIGNOR TO THE CU'JLER- incassi'.

Application. 'flied November 12, i910.

Specification. of Letters )Patent MOTOFCONTROLLEB,

lo a part oiE this speciiication.

My invention relates to improvements in motor controllers. More particularly my in` vention relates to controllers for slrm'ing;` down electric motors, prior to stoppingthe same;

In practice there are many instances where it is extremely desirable. and in fact a requirement, to bring the load operated by the motcr to rest in a certain position or positlonswith a nc degree of accuracy. To do this requires. slow down ot the motor, prior to stopping the same. Furthermore. the desired slow down of 'the motor must ordinarily be accomplished within a predetermined period of time. lNhere a motor always operates under the saine load it is a simple vmatter to regulate the slow down to accurately bring the load to a standstill at the desired point or points and within the given lperiod of time. 1ilifhcre, however, the load is variable the problem is much Amore diiiicult.

One object of my invention is to provvlc a simple and etlicient controller which will insure accurate stopping of the motor and always within a given period of time Whether the load under which it operates be constant or/variable.

My inventiorpalso has various` other objects and advantages which will hereinafter be clearly and fully set forth.

In order to clearly and fully disclose the nature and advantages of my invention, l shall describe the controller diagranunatically illustrated in the accompanying draw ing, which embodies my invention in one form. Of course my invention is susceptible otl embodiment in various other forms, the controller illustrated in the accompanying drawing merely serving for the purpose of illustration.

-In the drawing is shown a motor l. having an armature A and a shunt iieid wind-- ing' l?. in series with the motor armature is a variable starting resistance R connected to a series ot' contacts 2. A pivotcd arm having'n contact brush adapted to sweep over :laid contacts 2 is provided for corr trolling said resistance l). The arm 3 is also provided with additional contactI brushes 5, (3, 7, 8 and 9. The contact brushes :3, 6 and 7 are electrically connected to one another but are insulated from the arm 3. (ontact brushes S and 9, on the other hand, are both electrically connected lo the arm The contact` brush el in addition to engaging contacts 2 is adapted to be moved over a contact segment a electrically connected to the contacts 2. Contact brushes 5, (l, 7, 8 and 9 are adapted to he moved over contact segments 5, 6, Y, il a nd 9"', respectively for the establishment o'lE the circuits hereinafter described. licsistanres 11,-?" and r2 are adapted to be conmscted in shunt with the motor armaturo by an elcctroresponsive switch l0 under the conditions and lor the purpose icereiuutter set forth. .For controllingA the resistant-.os r to r2, after tho fame lnave been connected in shunt with the motor armaturc. are fn'ovidcd electrorespfmsive switches ll` 2 conditions and with the results hereinafter Set forth. i

Vi shall now describe the operation of the controller at the same time clearly setting; forth the various circuit connections and the functions of thc various parts. lt may l e assumed that the motor is employed for raising' a load which i n v vary within prcdclcrmincd limits. i'lissuminaY the arm 3 to hc in the pnsition illustrated, themotor circuit will 'no open and the motor at rest. (if course, in practice where a motor is cmployed tor hoisting purposes, a mechanical brake is ordinarily provided to holdthe motor against movement after the same has come to rest. The motor may be started by nioi'ingr the arm 3 to the rightto bring contact brush et intoy engagement with contact segment 4. Assuming that current is supplied to the motor from supply lines 16 and i7, circuit will now be closed from supply line 16 through the arm 3 and contact brush 4 to cont-act segment L9; thence through the resistance B. by conductor 18 through the niotorarmature to supply line and 13 adaiitod to operate under the las illustrated, the motor will immediately 17. The shunt lield winding F being permanently connected across the supply lines,

begin to operate. Under these conditions, however, the motor will only operate at a slow speed, owing to the insertion of the resistance R in its armature'circuit. Upon continued movement of the arm 3 to the right, the contact brush f1 will pass over the contacts .2, gradually removing the resistance R until the motor has been brought up to normal speed. I'

Let it now be assumed that when the motor has operated to bring the load within a predetermined distance of the point at which it is to be stepped, the arm 3 is automatically moved in synchronism with the motel.' or load operated thereby, in an opposite direction to that just described. Movement ol` the arm 3 in. this direction reinserts the rc sistance R which slows down the motor. Oi course the slow down etl'ect of the resistance R is limited and is at its maximum when that arm 3 reaches contact segment 45. Con-f tinued automatic movement of the arm 3, however, brings the same into engagement with segment 9a. This completes a circuit from supply lines 16 through arm 3 and contact brush 9 to segment 9j* by conductor 2O through the operating winding of switch l0 to conductor 21 and thence to supply line 17. Switch 10 thereupon responds, connecting the resistances 7', 7" and r2 directly across the terminals of the motor armature. vJhe establishment of this shunt circuit, as is well understood by those skilled in the art, further slows down the motor to a degreedcm pendent upon the value of the resistanceiir eluded therein, while the speed of the motor may be still further decreased by decreasing said resistance. It is also understood thatjthe establishment of the shunt circuit above described will have a greater slow down effect uponthe motor when raising a heavy load than when raising a light load, the converse being true when the load is lowered. Accordingly, when theinotnr is operating under a light load in hoisting and under a heavy load in lowering, more resistance must be removed from the shunt cir` cuit to obtain the desired speed reduction, than when converse conditions prevail. To meet these conditions, I have 'made provision, whereby when the arm3 is moved to the next slow down position, contact brushes 5 and 6 will bridge contact segments 5a and 6". i This results in connecting the operating winding of switch 13 across the terminals of the motor armature fand therefore rendering the .sa-.me responsive to the counter electromotive force of the motor armature. The circuit thus established may be traced from the-left hand terminal of the motor armature by conductors 1S, 22 and 9.3 to contact segment .5, `thence to contact segment (ia by conductor 2d through resistance 25 and through the operating winding of switch 13 by conductor 2G and 27 to conductor 21 and thence to the right hand terminal of the motor armature. With these connections, if upon establishment of the shunt circuit described the speed .of the motor is not decreased to the desired degree owing to its having a. light load when raised or a heavy load when descending, the counter electr-emotive force ot` the motor armature will be suliicient to cause said switch 13 to respond. Switch 13 short circuits a portion of the resistance r2. Provision of the resistance 25 in series with the 8o operating winding of switch 13 prevents response of the switch '13. except when the counter electromotive iorce of the motor armature is at a predetermined minimum. Accordingly, said switch may be so regulated by said resistance as not to respond,- except under predetermined conditions and by variation of lsaid resistance, said switch "maybecauced to respond at any predetermined counter electromotiv'e force of the 90 motor armature. 'The closure of switch 13 does not immediately reduce the speed of the motor to the desired degree but as hereinafter described subsequently accomplishes this result. At the same time that the operating winding of switch 13 is connected .across the terminals of the motor armature,

contact brush 8 engages contact segment 8, completing a circuit from arm 3 by conductor 2S through the operating winding of 100 switch. 1l to conductor 27. Thereupon switch 11 responds, short circuiting the resistance r. This, ot course, tends to slow down the motor still further. When the arm 3 is moved still further to cause Contact 1-05 brush 7 to engage contact segment 7, the operating winding of switch 12 is connected in parallel to the operating winding of switch 13 across the terminals of the motor armature. This switch, vlike switch 13 iS 11C therefore responsive to the counter electromotive force of the motor armature, but unlike switch 13 it is designed to respond regardlcss of the load on the motor. In fact, it might be connected in parallel to the op- 111 erating windings of switches 10 and 1l, and therefore not be dependent upon the counter electromotive force of the motor armature for its energization. Switch'lQ in closing short circuits resistance r. This, of course, 12o tends to still further reduce the speed of the motor. v

Assuming now that the load on the motor is within predetermined limits and the switch 13 has not responded, the removal of 125 ,the resistances 7 and fr" from the shunt slow down circuit will cause a suflicient reduction in the speed of the motor to insureyaccurate stopping of the motor when its circuit is opened. Under these conditions all of the no incassi with the vswitch ll.' This would short cirlieved to be unnecessary.

'facilitate a clear understanding thereof.

cuitA a portion of the resistance Thus closure ofthe switch 13 augmente the. eilectivcness of the switches l1 and l). .and pre determines the amount of resistance lett in the shunt slow down circuit and by changing` between the switch predetermined permanently the point of connection lrl and the resistance r2 any amount of resistance may be included in said shunt circuit. Accordingly the provision of the switch 13 enables automatic regulation oi the slow down eil'ect of the shunt circuit in accordance with. the load under which 1the motor operates and further facilitates regulation of this automatic control in accordance with the particular conditions to be met with. That is to say, the switch 13 may be adjusted to leave more or less resistance permanently connected in the shunt circuit in accordance with the degree of variation oi' the load from the average.

lt will be observed that the switch 13 if it responds does so within-the period allowed 'for the successive operation et 'the switches l0, l1 and l2. lln other words, all four switches will respond within the saine period under conditions of variable load as is allowed for operation of three of the same under conditions of constant load. There- ;iore with the arrangement illustrated no additional time is required 'for meeting and compensating for lie conditions oit variable load. y

"it should be anderstood that the controller' herein illustrated and described has been re duced to a very simple orm in order to 0i' course, in practice, various additional features commonly controller7 lbut it has necessary toillustrate tice, the arm 37 or its ably operated either directly or through suitable means by the motor or the load operated thereby and in synchronism there-` with. Aarise, in practice meansinay be provided ttor reversing' the motor7 and the same or separate slow down means may be employed for controlling the ditions oi reversal.

`Various other additional 'features and reiii ements which are commonly used in practice might be herein set forth, brut this is bebeen considered unthe;` same. ln prac equivalent is prefer.

Having thus described my invention what l claim as new and desire to secure by Let-xl ters lgatent, is: l :f l. A motor controller comprising means operable to electrically slow down the motor, and means automatically responsive under certain load conditions to vary incorporated in such a' motor under con` the electrial eliect produced by said` first mentioned means at the time of its operation.

EZ. l'n a ycontroller for electric motors in combination, means 'for slowing downthc motor, and automatic means operatingv independently oi said first mentioned means under predetermined. load conditions to augment the slow down eii'ect on the motor, said second mentioned means operating if at all prior to i'ull -operation of said first mentioned means.

B; In a controller .for electric motors, in combination, means operable to gradually slow down the motor electrically and means adapted to operate automatically during the operation oi said first mentioned means under predetermined load conditions to augment the slow down effect upon. the motor. y

4l. ln a controller 'for electric motors, in combination, means operable to gradually slow down the motor and means adapted to operate automatically during the operation of said first mentioned means under predetermined load conditions to augment the slow down effect upon the motor, said first mentioned mea/ns being operable to its 4full extent without operation of said second mentioned means under predetermined load ccnditions.

5. ln a controller for electric motors, in combination., means operable to gradually slow down the motor7 and means responsive under predetermined. load conditions to cooperate with said ilrst mentioned means to increase the slow down ediect on the motor, said second mentioned means operating only upon a failure o'f said first mentioned means to slow down the motor -to the desired degrec upon a predetermined operation thereof and operating if at all prior to full operation 'of said Ylirst mentioned means.

6. In a controller for electric motors, in combination, a plurality of devices operable to slow down the motor, an auxiliary slow down device voperating automatically under predetermined conditions to augment the slow. down eii'cct on the motor, all of said first-mentioned devices being operable without operation oi said auxiliary device, but seid auxiliary device operating ii' at all during\ the operation of said first mentioned devices. l A

7. In a controller for electric motors in combination, a plurality oi? successively operated slow down devices for the motor, an auxiliary slow down device operating only when the combined eiect of all oi said first mentioned devices is inadequate to slow d wn the motor to the desired degree, but o` rating if at all prior to the operation of the last of said first mentioned devices.

8. ln a controller for electric motors in combination, a plurality of slow downl denio vices, an auxiliary slow down device operating automatically under predetermined load conditions to augment the slow down elect oit said lirst mentioned devices, said auxiliary device operating if at all during the operation olf said ti st mentioned devices but not until after a predetermined number' of said first mentioned devices have been operated.

9. ln a controller for electric motors, in combination, means operated independently of the load, conditions to slow down the motor and automatic means responsive to variations in the load conditions for varyingv the slow` down etl'ect of said first mentioned means, said second, mentioned means operating it at all during the operation of `:id tiret mentioned means.

10. In controller Ltor electric motors, in combination, a plurality of slow down switches, a separate automatic slow down switch directly responsive to the load conditions and operating` only when the combined slow down effect of the remaining` switches is insullicient to slow down the motor to the desired degree, said automatic switch ojierating if at all during the operation of the remaining switches.

ll. In a controller for electric motors, in combination, a plurality of slow down switches, a separate automatic slow down switch directly responsive to the load conditions and operating only when the combined slofdown ellect of the remaining switches insul'licient to slow down the motor to the desired degree, said automatic switch operating if at all during the operation of the remaining switches, and means for posi-- tively preventing operation of said automatic switch until a predetermined number of the remaining switches have been operated. y

l2. In a controller for electric motors, in combination, means for gradually slowing down the motor and means rendered responsive to the counter electromotive force oil the motor armature prior to the full operation oil' said i'irst mentioned means, to augment theA ell'ectivencss oi" said first nnen` tioned means upon variations in the load on the motor.' i

13. In a controller for electric motors, in

combination, a plurality of successively operated slow down switches, an auxiliary slow down switchresponsive to the counter la. In a controller for electric motors, in

combination, a variable resistance connected in shunt with themotor arnjiature, means for gradually. removing a predetermined 'amount of said resistance to slow down the motor and means operating automatically upon variations in the load imposed upon the motor and prior to the full operation of said first mentioned means, to vary the resistance not controllable by said first mentioned means.

lo'. In a controller for electric motors, in combination, a variable .resistance connected in shunt with the motor armature, means for gradually removing a predetermined amount of said resistance to slow down the motor and means operating automatically upon variations in the load imposed upon the motor and prior to the full operation ot' said first mentioned means to vary the resistance not controllable by said rst mentioncd means, said second mentioned means being responsive to the counter electromotive torce of the motor armature.

16. In a controller for electric motors, in combination, a variable resistance connected in shunt with thenotor armature, va plurality ol" successively.actuated switches for short circuiting portions of. said resistance to slow down the motor, a switch adapted to vary that portion'of said resistance not controllable by said first mentioned switches, said second ,mentioned switches having an operating winding connected across the terminals of the motor armature and responding, if at all, prior to the operation of one of said first mentioned switches.

In witness whereof, I have hereunto subscribed my name in the presence of two witnesses.

CHARLES E. HYATT.

Witnesses:

T. E. Bannon,

FRANK H. HUBBARD. 

